view tests/test-issue1175 @ 8849:80cc4b1a62d0

compare grep result between target and its parent

I found that typical case is that grep target is added at (*) revision
in the tree shown below.

     +--- 1(*) --- 3
     0
     +--- 2 ------ 4

Now, I expect 'hg grep --all' to show only rev:1 which is first
appearance of target line.

But 'hg grep --all' will tell:

  target line dis-appeared at 3 => 4
  target line     appeared at 2 => 3
  target line dis-appeared at 1 => 2
  target line     appeared at 0 => 1

because current 'hg grep' implementation compares not between target
revision and its parent, but between neighbor revisions in walkthrough
order.

I checked performance of this patch by "hg grep --follow --all
walkchangerevs" on whole Mercurial repo, and patched version could
complete as fast as un-patched one.

#!/bin/sh
rm -rf a
hg init a
cd a
touch a
hg ci -Am0
hg mv a a1
hg ci -m1
hg co 0
hg mv a a2
hg up
hg ci -m2

touch a
hg ci -Am3
hg mv a b
hg ci -Am4 a
hg ci --debug --traceback -Am5 b
hg verify
hg export --git tip